This application claims priority to Korean Patent Application No. 2003-40105, filed on Jun. 20, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to an actuator for a data storage device such as a HDD (hard disk drive) for example, and more particularly, to a suspension with a stiffened end-tab for the actuator.
2. Description of the Related Art
A hard disk drive (HDD) is a computer data storage device, which reproduces data stored on disks or records data on the disks using read/write heads. In the HDD, the head operates by being moved to a desired position over a disk by an actuator as the head is lifted above the disk by a predetermined height.
When the HDD does not operate (i.e., when the disk is not rotating), the head should be parked in a position other than over any data recording surface of the disk so as not to touch the data recording surface of the disk. Such a head parking system is roughly classified into either a contact start stop (CSS) system or a ramp loading system. In the CSS system, a parking zone is formed for parking the head on an inner peripheral surface of the disk. In the ramp loading system, a ramp is installed outside the disk to park the head on the external ramp.
In the CSS system, since the parking zone is formed on the inner peripheral surface of the disk with no data being recorded on such a parking zone, data storage space is disadvantageously wasted. Thus, for higher data recording density, the ramp loading system is the preferred head parking system since a parking zone on the disk is not used resulting in larger data storage space.
FIG. 1 is a schematic plan view of a HDD using a conventional ramp loading mechanism for the head parking system. FIG. 2 is a perspective view of a ramp and a suspension with a dimple-shaped end-tab in the HDD of FIG. 1. FIG. 3 is a longitudinal sectional view of the suspension with the end-tab of FIG. 2.
Referring to FIGS. 1 through 3, the HDD includes a base plate 10, a spindle motor 12 installed on the base plate 10, one or more disks 20 mounted on the spindle motor 12, and an actuator 30 for moving a slider 34. A read/write head for data reproduction and recording is mounted on the slider 34 that moves the head to a predetermined position on the disks 20.
The actuator 30 includes an actuator pivot 31 installed on the base plate 10, a swing arm 32 rotatably coupled with the actuator pivot 31, a suspension 33 installed at one end of the swing arm 32 for elastically supporting the slider 34 toward a surface of the disks 20, and a voice coil motor (VCM) for rotating the swing arm 32. The VCM includes a VCM coil 39 coupled with the other end of the swing arm 32, a lower yoke 37 disposed under the VCM coil 39, and a magnet 38 attached to a top surface of the lower yoke 37. The VCM may further include an upper yoke (not shown) disposed on the VCM coil 39 and a magnet (not shown) attached to a bottom surface of the upper yoke.
The VCM is controlled by a servo control system and rotates the swing arm 32 in a direction based on Fleming's left-hand rule due to interaction between current input to the VCM coil 39 and a magnetic field formed by the magnet 38. For example, when the HDD is turned on and the disk 20 begins to rotate in an arrow direction D, the VCM rotates the swing arm 32 counterclockwise (in an arrow direction A) to move the slider 34 with the mounted read/write head 35 to a position above a data recording surface of the disk 20. The slider 34 is lifted above the surface of the disk 20 by a predetermined height due to a lift force generated by the rotating disk 20. At this time, the head 35 mounted on the slider 34 reproduces data from or records data on the data recording surface of the disk 20.
In the case when the HDD is not operating with the disk 20 not rotating, the head 35 should be parked in a position that is not any data recording surface of the disk 20 so as not to touch any data recording surface of the disk 20. For this purpose, a ramp 40 is installed outside the disk 20, and the suspension 33 has an end-tab 36 protruding at a distal end of the suspension 33. When the head 35 is parked on the ramp 40, the actuator 30 is locked into a parked position by an actuator latch 50 to prevent unintentional rotation about the pivot 31 from external impact.
Referring to FIGS. 2 and 3, the ramp 40 includes a fixed portion 41 fixedly attached to the base plate 10, and a support 42 extending from the fixed portion 41 toward the disk 20 and overlapping with an outer edge of the disk 20. The support 42 has a support surface 43 for supporting the end-tab 36. An end portion of the support surface 43 disposed toward the disk 20 is inclined such that the end-tab 36 is smoothly loaded and unloaded.
When the HDD is turned off and the disk 20 starts to slow its rotation, the VCM rotates the swing arm 32 clockwise (in an arrow direction B). Accordingly, the end-tab 36 is unloaded from being over the disk 20 and is parked onto the support surface 43 of the ramp 40. Alternatively, when the HDD is turned on and the disk 20 begins to rotate, the end-tab 36 is moved from the support surface 43 of the ramp 40 and is loaded over the disk 20. Such unloading and loading of the end-tab 36 is achieved with the rotation of the swing arm 32 using the VCM as described above.
In the ramp loading mechanism for the head parking system, the end-tab 36 contacts the support surface 43 of the ramp 40 often, resulting in friction between the end-tab 36 and the support surface 43. For minimizing such friction, the conventional end-tab 36 has a hemispherical shape such as a dimple shape for example with a projecting part toward the support surface 43. Such as dimple shape of the end-tab 36 reduces contact area between the end-tab 36 and the support surface 43 of the ramp 40, as illustrated in FIG. 3.
When the end-tab 36 is moved from the disk 20 and then is placed on the support surface 43 of the ramp 40, a large load is applied to the end-tab 36. If the end-tab 36 is not stiff enough to support the load, a portion A illustrated in FIG. 2 of the suspension 33 may be bent. With such bending, the slider 34 attached to the suspension 33 does not separate quickly from the disk 20, and the time for unloading the end-tab 36 is lengthened. As a result, the performance of the HDD disadvantageously deteriorates. Furthermore, repetition of loading and unloading the slider 34 with such bending for a long period of time may damage the end-tab 36.
To prevent the aforementioned problems, it is desirable to enhance the stiffness of the end-tab. For example, the size and thickness of the end-tab may be increased for increasing the stiffness. However, such increase in size and thickness also raises the weight of the end-tab which undesirably decreases the driving performance of the actuator. Accordingly, a small and light end-tab having high stiffness is desired.
FIGS. 4 through 6 illustrate a suspension with a canoe-shaped end-tab suggested to prevent the above problems, as disclosed in U.S. Pat. No. 6,181,529. Referring to FIGS. 4 through 6, an end-tab 62 longitudinally extends from a distal end of a suspension 61. The end-tab 62 has a canoe-shape with a constant width along the length of the end-tab 62. A surface 63 of the end-tab 62 contacting a support surface of a ramp is curved such that a contact area between the end-tab 62 and the support surface of the ramp is minimized. The canoe-shaped end-tab 63 may have a high enough stiffness to be applied for a 2.5-inch disk having a data storage capacity of 40 GB.
With constant demand for higher data recording density, an overlapping area between a support of a ramp and a disk is desired to be decreased to enlarge the data recording surface of the disk. For example, efficient operation for a relatively small 2.5-inch HDD disk within a notebook computer demands further reduction of the overlapping area between the support of the ramp and the disk. For such reduction of the overlapping area, loading and unloading of the end-tab should be more rapidly performed resulting in greater load on the end-tab.
Unfortunately, the canoe-shaped end-tab of the prior art is typically not stiff enough to be applied to a disk having a data storage capacity greater than 40 GB. Therefore, an end-tab is desired to be stiff enough to be applied within a disk drive with such greater data storage capacity.